Automatic pilot for small boats



. MN [FOB Nm v, NM NM mw M. 4/ WW m m m N N Q 3mm NM wm w H W & N v j 4 n Q -w\ Q) wmwmxsu M MJ RM I W 9v wm MW m u f mm A m w wh Q mks m 0Q 06k 98 mfi wm fik mm, V, w 4,.

March 1, 1966 L. F. JOHNSON AUTOMATIC PILOT FOR SMALL BOATS Filed Sept. 24, 1964 United States Patent 3,237,583 AUTOMATIC PILOT FOR SMALL BOATS Lloyd F. Johnson, 391 La Perle Place, Costa Mesa, Calif. Filed Sept. 24, 1964, Ser. No. 398,842 2 Claims. (Cl. 114-144) This invention relates to an automatic pilot for small boats, more particularly boats that have their rudders controlled by tillers, rather than those that are controlled by wheel helms.

'An object of the present invention is to provide an automatic pilot that embodies means to correct or adjust the course of a small craft by means operated by a reversing motor, the latter changing its polarity in response to control circuit means energized by compass-controlled, lightsensitive cells.

Another object of the invention is to provide an automatic pilot, as above characterized, in which the compass case is mechanically linked to a tiller-engaging yoke as part of the means operated by the motor.

A further object of the invention is to provide means employing said light-sensitive cells to sense changes in the course of the craft relative to the course to which the compass had been set.

A yet further object of the invention is to provide an automatic tiller controller that, while having operative connection with the tiller, is yet capable of rapid and simple installation and removal, as desired.

A still further object of the invention is to provide a device of the character referred to that is of unitary design, easily detached from engagement with the tiller, and readily removed from the boat in its entirety. Prior automatic pilots required complicated electrical installation Which rendered it unfeasible to remove the device as occasion required.

This invention also has for its objects to provide such means that are positive in operation, convenient in use, easily installed in a working position and easily disconnected therefrom, economical of manufacture, relatively simple, and of general superiority and serviceability.

The above objects are realized in a unitary device in which the card of a gimbal-mounted compass is provided with a shield that, when the craft is on course, intercepts the rays of a light above and centered on the compass. The compass case mounts two diametrally opposite lightsensitive cells, one or the other of which is exposed to receive rays from said light when the craft veers off course in one direction or the other. Relay means are operated by electric circuits that are closed by said cells, the same, depending on which cell is excited or energized, providing an operating motor with polarity to turn it in one direction or the other. The operating motor drives tiller moving means that is also connected to the compass case to turn the same in a direction to shut off light from the cell that had been excited. The unexcited cell then opens the circuit to the relays and, therefore, the circuit to the motor is opened and the correction movement of the tiller stops. The corrected course will be maintained until one or the other of the light-sensitive cells is excited.

The invention also comprises novel details of construction and novel combinations and arrangements of parts, which will more fully appear in the course of the following description and which is based on the accompanying drawing. However, said drawing merely shows, and the following description merely describes, one embodiment of the present invention, which is given by way of illustration or example only.

The figure is a schematic view of the present automatic pilot.

The automatic pilot that is illustrated comprises,.generally, a compass that is gimbal-mounted in the usual "ice way and is represented in the drawing by its case 5 and its north-seeking card 6, a lamp 7 or other illuminating means disposed preferably above the compass and centered thereon, two light-sensitive cells or sensors 8 and 9 carried by the case in diametrally opposite positions, a shield 10 carried by the card 6 to mask or expose said sensors from the light of lamp 7 according to the relative rotation-a1 relationship between the compass case and card, a reversible DC. motor 11, a relay circuit 12 connected to the sensor 8 and connecting the motor 11 to a dry cell battery 13 or other direct current source so the motor has polarity to turn in one direction, a similar relay circuit 14 connected to the sensor 9 and connecting the motor 11 to said dry cell battery so the motor has opposite polarity to turn in a reverse direction, means 15 driven by the motor 11 in one direction or the other according to which sensor 8 or 9 is excited by light from the lamp 7, a tiller-engaging yoke 16 moved by said means -15 to cause the tiller to move the rudder connected thereto, accordingly, and linkage 17 connecting said yoke 16 and the compass case 5 to restore the latter to a position that replaces the excited sensor behind the shield 10 and, thereby, cause de-energization of said sensor and the motor 12 and corresponding relay circuit. All of the above, except the north-seeking card 6, are so placed on the boat as to turn with it.

The sensors 8 and 9 act asJwitches that are normally open and which close upon excitation or energization by light.

The shield 10 may comprise any suitable masking member aflixed to the card 6 and is preferably of semicircular form so that it will intercept light to both sensors and will expose one or the other sensor, but not both at the same time, to the light of lamp 7. Said shield may be adjustably mounted on thecompass card, if desired, the adjustment being a circumferential one.

The relay circuit 12 comprises a dry cell battery or similar current source 20 that provides current to light the lamp 7 and is in series with the coil 21 of a relay 22 and the sensor 8 by means of conductors 23 and 24. A switch 25 is actuated by said coil 21, the same being connected by a conductor 26 to one terminal or pole 27 of the DC. motor. Said switch 25 normally has contact with a terminal 28 which, through the battery 13, is connected by a conductor 29 to one side of a switch 30. Said terminal 28 and battery 13, by a conductor 31, are also connected to one side of a similar switch 32.

The relay circuit 14, in a similar manner, comprises the coil 33 of a relay 34 and the sensor 9 connected to said latter coil, through conductors 35 and 36. A switch 37 is actuated by said coil 33, the same being connected by a conductor 38 to the other terminal or pole 39 of said DC motor. Said switch 37 normally has contact with a terminal 40 which is connected by a conductor 41 to the same pole of battery 13 to which the terminal 28 is connected. Thus, the terminal 40 is also connected through said battery 13 and conductor 29 to the switches 30 and 32.

The means 15 is shown as reducing gearing 42 that connects the reversible motor with a lead screw 43 that is mounted to rotate in bearings 44 at the ends thereof; and a nut 45 on said screw and which is caused to traverse in one direction or the other along the screw according to the direction of screw rotation.

The yoke 16 is affixed to the nut 45, the tiller being engaged therein in a manner, as shown, that enables the same to be separated from the yoke for manual control.

The linkage 17 is shown as an arm 46 fixedly extending from the compass case 5, and link 47 that, at one end, has a pivotal connection 48 with the end of arm 46. Said linkage is exemplary of means that interconnects the yoke and compass case so that the latter will turn in a direction according to the direction of traverse of the yoke 16. Lazy tongs may replace the link 47, as an example of alternative means.

Operation Assuming the yoke 16 is at the middle of the lead screw 43 where it will normally be located when the rudder of the boat is in its on course position, both sensors 8 and 9 are masked by the shield 10, the compass card 6, mounting said shield, being magnetically held in its north-seeking position, as the boat travels its pre-determined set course.

If, for any reason, the boat veers to the right, all of the above-described means turns right, except the card 6. The light from lamp 7 will then fall on sensor 8 which, acting as a switch, closes the circuit through battery and conductors 23 and 24, to energize the coil 21 of relay 22. Switch 25 will then be drawn away from terminal 28 to engage terminal of a conductor 51 connected to the opposite side of switch 32. The following circuit is thus established: switch 25, conductor 51, switch 32,

conductor 31, battery 13, conductor 41, relay switch 37, and conductor 38 to terminal 39 of the DC. motor. Since conductor 41 is connected to the positive side of battery 13, and terminal 39 is positive and the motor will rotate in a direction to turn the lead screw in the direction of arrow 52 and causing traverse of the yoke 16 in the direction of arrow 53, restoring the shielded relationship of sensor 8 due to the left rotation of the case 5 by linkage 17, according to arrow 54. The circuit to coil 21 will now be interrupted and switch 25 will return (by spring bias) to the contact 28, opening the circuit to said terminal 39 and causing the motor to stop, and stopping the yoke 16 with the tiller in its new position. The boat rudder will, therefore, cause the boat to steer a corrected course in a left turn when everything turns with the boat, except the card 6, as before.

If during this correcting left turn, the sensor 9 is unmasked, the relay coil 33 will become energized and the switch 37 will be drawn into contact with a terminal 55 of a conductor 56 connected to the opposite side of switch 30. The following circuit is thus established: switch 37, conductor 56, switch 30, conductor 29, battery 13, relay switch 25, and conductor 26 to terminal 27 of the DC. motor. Since the switch 25 is connected to the positive side of battery 13, said terminal 27 is positive and the motor will turn in the reverse direction from that above described. As a result, the lead screw 43 will turn in the direction of arrow 57, the yoke 16 will move according to arrow 58, and the linkage 17 will turn compass case 5 in the direction 59 to restore the shielded relationship of sensor 9, causing the motor tostop and bringing the boat back on course, according to the pre-set position of the compass case.

This type of operation, in one direction or the other, automatically is set in motion upon one or the other sensor being excited by the illumination of lamp 7.

It will be clear that the present device uses only enough rudder to keep the boat on course, the course-correcting cycles occurring according to the speed that the boat responds to its rudder. Boat speed affects rudder response, the response being faster at higher speeds and requires less correction than at lower boat speeds.

The switches 30 and 32 may be manual but may be located, as shown, to act as limit switches that are opened by the yoke 16 under conditions that may cause extreme traverse.

The device comprises a self-contained unit that may be readily detached from engagement with the tiller and carried off the boat. The outline 60 represents an enclosure to contain the present mechanism and its electrical connections.

While the foregoing has illustrated and described what is now contemplated to be the best mode of carrying outthe invention, the construction is, of course, subject to modification without departing from the spirit and scope of the invention. Therefore, it is not desired to restrict the invention to the particular form of construction illustrated and described, but to cover all modifications that may fall within the scope of the appended claims.

Having thus described this invention, what is claimed and desired to be secured by Letters Patent is:

1. An automatic pilot for boats having a rudder that is controlled by a tiller and having a compass with a north-seeking card and a rotational case therearound, said pilot comprising:

(a) a lamp disposed to direct light onto the compass to illuminate the card,

(b) two light-sensitive sensors mounted on diametrally opposite sides of said case and which, when exposed to said light, change from normally-open switches to circuit-closing switches,

(c) a shield mounted on the card to shield both sensors from the light when the compass case and card are in an on course relationship,

(d) a relay connected in electric circuit with each sensor and having a switch that is shifted from one position to another upon excitation of said relay when a sensor is exposed to light when the case and card assume an off course relationship,

(e) a reversible DC motor having two poles, one connected to one relay switch and the other to the other relay switch,

(f) a source of direct current connected by one of its poles to both said relay-controlled switches to form a circuit that directs the current of said source to the pole of the motor that is in circuit with the switch that is moved by an excited relay, the motor rotating in a direction corresponding to which sensor is exposed,

(g) means driven by said motor and engaged with said tiller to shift the same in a direction corresponding to the direction of rotation of the motor, said means comprising a reducing gear, a lead screw rotated by said gear in a direction conforming to the motor rotation, and a tiller-engaging yoke provided with a nut engaging said lead screw, and

(h) means connecting the driven means to the case to turn the latter and the sensors thereof to bring the sensors to light-shielded position.

2. An automatic pilot for boats having a rudder that is controlled by the tiller and having a compass with a north-seeking card and a rotational case therearound, said pilot comprising:

(a) a lamp disposed to direct light onto the compass to illuminate the card,

(b) two light-sensitive sensors mounted on diametrally opposite sides of said case and which, when exposed to said light, change from normally-open switches to circuit-closing switches,

(c) a shield mounted on the card to shield both sensors from the light when the compass case and card are in an on course relationship,

((1) a relay connected in electric circuit with each sensor and having a switch that is shifted from one position to another upon excitation of said relay when a sensor is exposed to light when the case and card assume an off course relationship,

(e) a reversible DC motor having two poles, one connected to one relay switch and the other to the other relay switch,

(f) a source of direct current connected by one of its polse to both said relay-controlled switches to form a circuit that directs the current of said source to the pole of the motor that is in circuit with the switch that is moved by an excited relay, the motor rotating in a direction corresponding towhich sensor is exposed,

(g) means driven by said motor and engaged with said tiller to shift the same in a direction correspond 5 6 ing to the direction of rotation of the motor, said (j) a link connecting the end of said arm and the nutmeans comprising a nut-provided yoke engaged with provided yoke.

the tiller, and means operated by the motor to shift said member in a direction conforming to the rotation References Cited by the Examiner of the motor, 5 UNITED STATES PATENTS (h) means connecting the driven means to the case 2 102 512 12 1937 Chance 31 .4 9 to turn the latter and the sensors there-of to bring 2,864,990 12/1958 HILL 114-144 X the sensors to light-shielded position, (i) a rigid arm extending from the case in a radial MILTON BUCHLER, Primary Examinerdirection, and 10 ANDREW H. FARRELL, Examiner. 

1. AN AUTOMATIC PILOT FOR BOATS HAVING A RUDDER THAT IS CONTROLLED BY A TILLER AND HAVING A COMPASS WITH A NORTH-SEEKING CARD AND A ROTATIONAL CASE THEREAROUND, SAID PILOT COMPRISING: (A) A LAMP DISPOSED TO DIRECT LIGHT ONTO THE COMPASS TO ILLUMINATE THE CARD, (B) TWO LIGHT-SENSITIVE SENSORS MOUNTED ON DIAMETRALLY OPPOSITE SIDES OF SAID CASE AND WHICH, WHEN EXPOSED TO SAID LIGHT, CHANGE FROM NORMALLY-OPEN SWITCHES TO CIRCUIT-CLOSING SWITCHES, (C) A SHIELD MOUNTED ON THE CARD TO SHIELD BOTH SENSORS FROM THE LIGHT WHEN THE COMPASS CASE AND CARD ARE IN AN "ON COURSE" RELATIONSHIP, (D) A RELAY CONNECTED IN ELECTRIC CIRCUIT WITH EACH SENSOR AND HAVING A SWITCH THAT IS SHIFTED FROM ONE POSITION TO ANOTHER UPON EXCITATION OF SAID RELAY WHEN A SENSOR IS EXPOSED TO LIGHT WHEN THE CASE AND CARD ASSUME AN "OFF COURSE" RELATIONSHIP, (E) A REVERSIBLE D.C. MOTOR HAVING TWO POLES, ONE CONNECTED TO ONE RELAY SWITCH AND THE OTHER TO THE OTHER RELAY SWITCH, (F) A SOURCE OF DIRECT CURRENT CONNECTED BY ONE OF ITS POLES TO BOTH SAID RELAY-CONTROLLED SWITCHES TO FORM A CIRCUIT THAT DIRECTS THE CURRENT OF SAID SOURCE TO THE POLE OF THE MOTOR THAT IS IN CIRCUIT WITH THE SWITCH THAT IS MOVED BY AN EXCITED RELAY, THE MOTOR ROTATING IN A DIRECTION CORRESPONDING TO WHICH SENSOR IS EXPOSED, (G) MEANS DRIVEN BY SAID MOTOR AND ENGAGED WITH SAID TILLER TO SHIFT THE SAME IN A DIRECTION CORRESPONDING TO THE DIRECTION OF ROTATION OF THE MOTOR, SAID MEANS COMPRISING A REDUCING GEAR, A LEAD SCREW ROTATED BY SAID GEAR IN A DIRECTION CONFORMING TO THE MOTOR ROTATION, AND A TILLER-ENGAGING YOKE PROVIDED WITH A NUT ENGAGING SAID LEAD SCREW, AND (H) MEANS CONNECTING THE DRIVEN MEANS TO THE CASE TO TURN THE LATTER AND THE SENSORS THEREOF TO BRING THE SENSORS TO LIGHT-SHIELDED POSITION. 